Ortofon A90 or Air Tight PC-1

Dear Ldorio, if one happen to play - from time to time ... - microgroove records manufactured between 1954 and say 1990 (and I guess thats still the huge majority of vinyl out there - AND of interest) then you will encounter so many different (and huge differences indeed) cutting angles in cutting lathes between the early Fairchild to the later Neuman (and between individual samples of the same lathe-type) that the difference in groove-compliant SRA between say a Opus 3 and a Mercury SR90000 (two extremes of the range) results in about 1/2" in heights at the tonearm base of a 9" tonearm.
Back in the old days of the Mercury/RCA-collectors circle ( Sid Marks, Bob Corsetti, David Nemzer, Carol Keasler and a few others - including myself as a late member in 1988) in the later 1980ies, that was common knowledge among analog audiophiles and the VTA was precisely fine-tuned for the setting for each of the labels of interest (DECCA SXL, EMI ASD, RCA LSC etc.).
Back then none of us would have talked about VTA in any other context but groove (label....)-compliant.
Correct SRA and VTA is a direct function of the cutting angle of the record-groove in conjunction with the polished area of the stylus.
And the engineers at Ortofon-laboratories will confirm that.
IEC standards? You visit the remaining record plants and will still find many different cutting angles around.
Ever wondered why the ET2 or the early Wheaton Triplanar back in the late 1980ies/early 1990ies were that popular among serious record collectors going for the ultimate in sound (we have to include - now that's a surprise ! - the FR-64s w/B60 vta-on-the-fly base here for addressing this issue as early as 1979) ?
Because they featured easy change of VTA and precise return to earlier and different VTA settings.

Well, this has become quite an interesting discussion about the A90, SRA and grove cutting angles. There doesn't seem to be that much discussion about the PC-1. I have come to appreciate the need to adjust VTA/SRA with the A90 and because that is not the easiest adjustment to make on the SME V, and certainly not "on the fly", I'm rapidly getting the impression that on the basis of adjustability alone, the SME V and A90 may not be an ideal combination. Thank you for all of the information on this thread.

Dear Peterayer, whether the A90 and the SME V are or are not an ideal combination has nothing to do with VTA.
It has a lot to do with the effective mass of the "V", the body mass and compliance of the A90 and the general alignment you are making (to name just the "cornerstones").
I for one would rather recommend using the A90 in the SME V.
Aside from my personal opinion that the A90 is the "better sounding" cartridge of the two, its technical parameters will nicely match the mechanical/dynamic parameters of the SME V.
VTA is a matter of dedication and the will to go the extra mile time and again to get the very best out of ANY given tonearm/cartridge combination.
It wouldn't be any other way with the PC-1... or any other cartridge .... in any other tonearm.

@ Dertonarm

Very interesting information, indeed. Thanks!

Hi Dertonarm,
I understand your point about VTA. I'm just saying that I've had difficulty making very small VTA adjustments in my SME V arm. A dial-type tower like that on the TriPlanar with markings would be much easier. I don't change VTA depending on record thickness because of this.